Avalanche Forecast

Issued: Apr 8th, 2015 9:15AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Loose Wet and Cornices.

jlammers, Avalanche Canada

South Rockies.

Daytime warming will be driving the Avalanche Danger on Thursday. Watch for conditions that change with aspect, elevation and time of day.For details on how we issue Spring Danger Ratings, check out the latest Forecaster Blog.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

On Thursday and Friday morning, a dry ridge will maintain sunny skies and strong diurnal temperatures swings. Increased cloud should develop throughout the day on Friday. By Friday evening, we can expect light snow (up to 5cm) and cooler temperatures which should continue into Saturday. Daytime freezing levels should hover around 2300m on Thursday, 2000m on Friday and about 1500m on Saturday. Ridgetop winds will be light on Thursday, and then become strong from the southwest with Friday and Saturday's system.

Avalanche Summary

Observations are becoming more limited as we enter into spring. If you're out in the mountains, please consider posting your observations to our webpage using the Mountain Information Network. With freezing levels rising and lots of sun expected on Thursday, lots of natural sluffing is expected from steep sun-exposed slopes. Cornices will become weaker and may fail naturally. Thin wind slabs may also be sensitive to human triggering on isolated high elevation, lee slopes.

Snowpack Summary

10-20cm of recent snow overlies a widespread and supportive melt-freeze crust. In some areas, winds may have redistributed the surface snow resulting in wind slab formation in the alpine and exposed areas at treeline. Large cornices exist in the alpine and may become weak with daytime warming. The mid-March rain crust is down 35 to 70cm and has shown a good bond with snow above. Old persistent weak layers are still intact in the mid and lower snowpack and there may be potential for these layers to wake up with a big cornice fall, sustained warming and/or a significant rain event.

Problems

Loose Wet

Watch for pushy loose wet avalanche activity on sun exposed slopes. Loose wet avalanches can entrain mass quickly and travel long distances.

Minimize exposure to sun exposed slopes when the solar radiation is strong.>Be cautious of sluffing in steep terrain.>Be alert to conditions that change with aspect, elevation and time of day.>

Aspects: North, North East, East, South East, South, South West.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

Large cornices at ridgetop may fail under the weight of a person. Remember that destructive cornice falls become more likely during periods of warming and solar radiation.

Give cornices a wide berth when traveling on or below ridges. Remember that cornices become weak with daytime heating.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Apr 9th, 2015 2:00PM